This invention relates generally to an improved oil separator for a compressor, and more particularly to a compact oil separator which may be incorporated into a rotary sliding vane compressor especially adapted for use in an automotive air-conditioning system, and will be described in that environment.
In a rotary sliding vane compressor for an air-conditioning system lubricating oil is continuously needed to lubricate the moving components, to seal the high and low pressure sides of the compressor from each other, and, in some cases, to provide a cushion of pressurized oil underneath the vanes to urge the vanes toward the cylindrical wall of the compression chamber. This oil eventually leaves the compressor entrained in the refrigerant discharge gas and unless the oil is separated from the discharge gas and recirculated within the compressor the performance of the compressor as well as the air-conditioning system will be impaired. Specifically, if the compressor is deficient in oil the moving parts will be insufficiently lubricated and the required sealing between the high and low pressure sides will not be attained. In addition, substantial quantities of oil flowing out of the compressor with the refrigerant gas reduces the heat transfer in the condenser and evaporator.
Separation of oil from a gas is especially difficult when the density of the gas is very high, as may be the case with a compressor incorporated in an automotive air-conditioning system. The problem is additionally compounded, however, when it is desired to separate a large quantity of oil within a relatively small space, as is the case in an automotive rotary vane compressor. Re-entrainment of oil into the already-separated refrigerant gas and re-entrainment of refrigerant, as gas bubbles, into the already-separated oil is particularly difficult to avoid when the space limitations are severe. A still further complication to the problem arises when it is desired to achieve high oil separation efficiency throughout the compressor's speed range and at both low and high flow conditions.
The present invention overcomes this complex problem by providing a compact oil separator which requires very little space and may be integrated into a rotary vane compressor. Highly efficient oil separation is obtained at all flow conditions and at all compressor speeds, and yet there will be minimal, if any, re-entrainment of either the gas or oil into the other.